The objective of this project is to identify anticaries agents suitable for short-term clinical trials. Screening is conducted both in vitro and in animals. The in vitro studies measure minimal inhibitory concentration, and modification of enamel dissolution rate. Other measurements are used electively depending on the nature of the agent. The animal studies measure the effects of an agent on dental caries and plaque. Several bisguanides screened favorably providing marked inhibition of dental caries and plaque. A solution that changes some surface enamel to CaHPO42H2O (dical) promoted uptake of fluoride by the enamel with no change in its surface morphology. The effects of the dical forming solution on dental caries are being studied.